Interested in feedback/understanding on compressor surge. Esp in aftermarket turbos.

- Where how does it originate
- How to manage while driving
- How to tune it out (DV, WG, Porting, etc)

It seems achilles heel of a couple very different setups.
(HKS GTII, Original FP Red...etc)

Have you had it? How Did you fix/solve/diagnose it? Any recommendations?
Or: Just best to stick to stock? For 350-400 ish hp/tq

Thanks!

 

Don't short change yourself by eliminating your options before you really know the ins and out of what Surge is and happens.. For instance some have reported surge problems with the HKS GTII you mentioned and I have read them, I have the same turbo and I have no issues, several others have the same turbo, NP's.. Just cautionary advise. Good luck.

 

Thanks...appreciate your perspective for sure

BTW, not tring to single out HKS (edited first post), and it looks like promising alt to IX unit
What setup (in/ex) are you running w/ your GT II that has it working for you?

Tks!

 

Bumping for more feedback Anyone?

 

Humble HKS GTII 7460R owner.I`m experiencing compressor surge on 4th and 5th gear on full boost 26PSI. I never had a surge issues before, after about six months of use turbo is surging big time. This also might be due to cold weather here in WI. I`m going back on a dyno in few weeks and checking my bov for leaks and changing my HKS WGA with a stronger unit.

 

It is 100% tunable. WGDC by gear, and a tiny bit of %TPS vs WGDC to clean up 3-4k in higher gears.

fast spooling efficient turbos can move more air than can fit through a partialy cracked throttle body. When the air is stalled in the charge pipe and the compresseor blades are going 20k RPM you will hear "surge".

I was initially worried because I had to back off my WGDC that it would feel laggy but it pulls hard to 30 PSI below the surge line with super snappy response.

 

^^^Good stuff I will mention this info to my tuner next week hopefully surging will go away. I bought FP 25PSI Actuator, do you think swapping WGA will cure some surging issues or should I keep an HKS actuator. Any recommended settings on HKS Actuator?

 

Surge is tunable. The less control there is over the boost, the harder it would be to tune around the boost possibly losing some top end.

 

Did you try replacing the BOV yet? If your "surging" is due to a boost leak and/or leaking BOV, then reducing WGDC will only reduce performance. It's like completely tearing an ACL, and instead of replacing the ligament, you just use a knee brace, and keep running on it. Ideally, you want to fix the issue without reducing boost, spool, etc.

 

I did every test in the book, no bov leak, neither boost or exhaust leak. They found small leak on shaft seal throttle body which I`ll be replacing with hi-pressure mil-spec and wanna change WGA see if that helps.

 

OK, good that you're at least narrowing it down. Hope you find the cause soon!

 

I had this problem a while ago but I had to stiff of a spring in my Tial and it wasn't opening all the way. Swapped out a lighter spring and it went away.

 

a stiffer wastegate spring will make compressor surge worse. compressor surge is the compressor moving more air than the engine can take. stiffer wastegate spring will alloy the turbo to spool yet even faster. what you need is a weaker wastegate spring. one that will slow spool a bit.

colder air is more dense. so the compressor can move more air at same given turbine speeds. Thats why you have surge now when you didnt have it six months ago. best fix for compressor surge is a shrouded compressor cover. this bypasses air back into inlet of cover during lower shaft speeds.

No one makes one for HKS turbo so one would have to be custom made.

 

^^^great answer thanks

 

Hi 94AWD,
say if im boosting at 1.6 & 1.8 bar with a Gt30 series turbo, what is the ideal WG spring rate should i put into my Turbosmart 38mm wg?